Repairing and Adding Bluetooth Control to an Induction Cooker

When his 6 years old induction cooker recently broke, [Johannes] decided to open it in an attempt to give it another life. Not only did he succeed, but he also added Bluetooth connectivity to the cooker. The repair part was actually pretty straight forward, as in most cases the IGBTs and rectifiers are the first components to break due to stress imposed on them. Following advice from a Swedish forum, [Johannes] just had to measure the resistance of these components to discover that the broken ones were behaving like open circuits.

He then started to reverse engineer the boards present in the cooker, more particularly the link between the ‘keyboards’ and the main microcontroller (an ATMEGA32L) in charge of commanding the power boards. With a Bus Pirate, [Johannes] had a look at the UART protocol that was used but it seems it was a bit too complex. He then opted for an IOIO and a few transistors to emulate key presses, allowing him to use his phone to control the cooker (via USB or BT). While he was at it, he even added a temperature sensor.

16 thoughts on “Repairing and Adding Bluetooth Control to an Induction Cooker”

Talking about gimmicks. Adding bluetooth control to a stove isn’t useful. You still need to stand by the stove to stir etc. so you might as well use the buttons located on the control panel for your convenience…

Picking the phone up and controlling the stove with greasy fingers doesn’t sound fun.

I can actually see some good uses for a BlueTooth stove.
1. Check to see if it is is on. Did you leave the stove on and forget?
2. Turn off the stove. See 1.
3. More for an Oven but the ability to check the temperature if you are preheating.
4. Start the oven preheating when you are on your way home from work… Maybe.
5. Set the clock. Really every time you access the device set the clock.
I would really rather see stuff like this interface to a central controller rather than just the smartphone. I would also like to see it use a slower 900mhz radio for longer range.

I left out that I would also not have a way to turn it on from the phone. I also just thought of a safety feature. Have the device cooktop turn off if you leave the house. AKA the Bluetooth device is out of range.

Perhaps it is not so clear, but I actually did manage to reverse engineer the UART-protocol and are using this to detect the current level of each zone. I can however not use this to set new power levels as the “keyboard” would not be aware of this and hence not update the display with correct levels. The “keyboard” also keep on sending the power levels every ~10s which would reset back any other power levels sent by me. I could of course remove the “keyboard” entirely, but it is kind of good to be able to control my induction hob without using my phone.

I was actually considering making my own keyboard/display for a while, but they have probably put serious amount of work in the touch detection which I then would have to redo so I was happy when I was able to intercept the key presses instead!

It depends on how much money you have. The thermostat assembly on my oven went bad causing it to always stay on. I had to unplug it and turn off the gas and wait 5 days or so for the replacement part to arrive. You can get by eating sandwiches or microwaving things.

Emulating keypresses is definitely the safest way of doing it. I was an app engineer intern at Microchip briefly, and I found that they actually have to implement a lot of safety features into induction cooktops. The primary concern is preventing oil flash fires. A thin layer of oil in a pan can heat to flash point extremely quickly. It’s something to be aware of if bypassing the management and control systems.

Great kitchen hack, and as for the sidenote i don’t really know 4HV but below is a short blurb of what might work to purify your barium carbonate:
If the iron contamination pieces as big, you could just use a magnet or you could do the following, react the barium carbonate with sulfuric acid, this will make barium sulphate and iron ii sulphate, iron sulphate is alot more soluble than barium sulphate and so you should endup with barium sulphate powder. To get back to barium carbonate heat up the barium sulphate with carbon to create barium sulphide, which is water soluble to this solution add sodium carbonate and you should end up with a Barium Carbonate precipitate